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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
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Products: Anyone heard of IQ glass? - What do forum members think of it?

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  1.  
    • CommentAuthorMike George
    • CommentTimeNov 28th 2009 edited
     
    From http://www.iqglass.com/products_iqglass/products_benefits2.html

    "If we do say so ourselves, our glass is a technological miracle."

    Is it?
    •  
      CommentAuthorJustin
    • CommentTimeNov 28th 2009
     
    Doesn't look anything out of the ordinary to me. Except perhaps for "electrical resistance that disperses heat equally" :confused:
    • CommentAuthorHairlocks
    • CommentTimeNov 28th 2009
     
    not really. I would think underfloor heating would heat a house better, probably be cheaper, and can use may different heat sources.
    •  
      CommentAuthorfostertom
    • CommentTimeNov 29th 2009
     
    Not clear - are they actually running a current thro the 'metal oxide' coating, to create heat?

    In principle, if e.g. windows are the biggest heat loss from a room, does it or does it not make sense to put the room's heat input right there, to supply the loss directly, so there's little or nothing to drive other heat-transfer activity elsewhere in and around the room?
  5.  
    Clear as mud isn't it. The lack of clear information makes me cynical.

    I just wondered whether anyone has any experience of using it - seems not
    •  
      CommentAuthorfostertom
    • CommentTimeNov 29th 2009 edited
     
    Posted By: fostertomare they actually running a current thro the 'metal oxide' coating, to create heat?
    My guess is, yes they are, as they also offering back-heated bathroom mirrors. So my question is
    Posted By: fostertomIn principle, if e.g. windows are the biggest heat loss from a room, does it or does it not make sense to put the room's heat input right there, to supply the loss directly, so there's little or nothing to drive other heat-transfer activity elsewhere in and around the room?
  7.  
    It doesn't make sense to me - No
    • CommentAuthorHairlocks
    • CommentTimeNov 29th 2009
     
    Heat loss is proportional to the heat difference. Trying to heat the room from the window, as there will always be loss through the walls, would make the heat difference across the window higher than not using a heating window. This would therefore increase the heat loss.

    Plus electricity is not the best source of heating energy
  9.  
    Yes, that was my original thought. Thanks.
    • CommentAuthorbrig001
    • CommentTimeNov 29th 2009
     
    So, if you wanted a minimum temperature of 20 degrees, but you the air around your windows was 2 degrees cooler than the rest of the room, you would need to heat the rest of the room to 22 degrees. If you add the two degrees to the air around your window, the rest of the room can now be 20 degrees. this would give a higher heat loss to the window, but lower to the rest of the room. Does it all balance out? Although, as Hairlocks said, electricity is not the best source of heating energy.
    • CommentAuthorbiffvernon
    • CommentTimeNov 29th 2009
     
    They say it gives succulant heat and sumptuous warmth, so presumably it's an energy sump that sucks.
  12.  
    Oh you cynic. They just mean it's good for the relatives of your cacti.
  13.  
    This is resistance heating applied to windows (distributed through the low-e coating.) Waste of time due to high primary energy demand - certainly not green. To achieve the same pane temperatures try triple glazing instead.

    Mark
    •  
      CommentAuthorfostertom
    • CommentTimeNov 30th 2009
     
    What if the resistance heating was applied to said triple glazing, thus supplying the room's principal heat loss right where it occurs?
  15.  
    I've got the brochure somewhere. I was looking at it for bathroom mirrors to stop them steaming up. The only reason why you'd bother with it IMO.
    • CommentAuthordickster
    • CommentTimeNov 30th 2009
     
    I put a 2d light fitting in a box which I recessed into the wall, stuck a bathroom mirror on the front of the box and scraped the silvering off all around the edge of mirror.

    You get your face lit up from all angles (makes me look much older than I really am) and no condensation , so you can shave in complete safety (apart from increased risk of electrocution, but what the hey).

    It works.
  17.  
    In what sense does it have a U value of 0.8?

    If it really does, that's amazing for double glazing and they should market that rather than the heating.
  18.  
    Tom,
    Life cycle primary energy of this stuff is daft. Can't understand why you're entertaining it.
    M
    •  
      CommentAuthorfostertom
    • CommentTimeDec 2nd 2009 edited
     
    By 'life cycle' you mean 'in use', not so much 'mining, manuf, transportation, construction and recycling?'

    If x amount of primary energy (however small) is going to be lost through any element e.g. glass, why is it better to have that primary energy x reach it indirectly by convection and radiation across the room from room-temp interior items, than to supply that primary energy x directly to the place it's being lost from? Either way, it's the same amount of primary energy x that's necessary to make up the room's shortfall in solar + incidental gain versus loss.
  20.  
    PE of elec is ~3, PE of gas ~1.1. IQ relies upon electric resistance whereas convective/radiation heat would hopefully result from gas or some other fuel with lower primary energy. So no, not the same PE for the two solutions.
    •  
      CommentAuthorfostertom
    • CommentTimeDec 3rd 2009
     
    Oh I see, yes of course, electricity for primary is crazy.

    Apart from that, Mark, as a ridiculous mind-experiment, what if the metal oxide coating were gas-heated @ 95% efficiency, to supply exactly the amount of heat that would be going out anyway from the room thro the glass - the point being that the heat is supplied direct to the place it's being lost, rather than indirectly by some back-up heating appliance in the house or by an electric element (eh?) in the MHRV supply duct?

    It's not an idle question - I agree putting such a heating input direct on the glass is a non-starter - but it could be applied as a principle more easily to walls and roof - if the principle has some advantage. I suspect there is a thermal advantage, as outlined at beginning of http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4936&page=1#Item_20 . I'd appreciate your view on this, Mark.
    •  
      CommentAuthordjh
    • CommentTimeDec 7th 2009 edited
     
    Work of the devil! :devil:

    As long as the biggest heat loss is through the window, you want its inside surface temperature as low as possible, to minimise the heat flow through it. As low as possible means "3 degrees less than room temp", according to PHI because of the constraint of thermal comfort, cold drafts etc. So heating the window is madness. If you need to heat it to get to even reach the -3 criterion (i.e. a conventional house with conventional glazing) then use conventional heating under it from gas or HP or whatever has lowest emissions.

    Same goes for the exterior walls. You want their surface temperatures low to minimise heat loss, not artificially high.

    Mirrors steam up because of high relative humidity. Use an extraction fan or open a door or window to reduce the humidity! Or do as dickster suggests.
    • CommentAuthorRobinB
    • CommentTimeDec 7th 2009
     
    "As long as the biggest heat loss is through the window, you want its inside surface temperature as low as possible, to minimise the heat flow through it."

    I'm going to copy the above comment to fostertom's discussion about "supplying heat to the loss place" or similar because I have been unconvinced about heating "the loss place" and djh's comment above seems to support my view.
    •  
      CommentAuthordjh
    • CommentTimeDec 9th 2009
     
    A small correction to my previous post, where I said: 'As low as possible means "3 degrees less than room temp", according to PHI'.

    I've just watched the videos of the excellent AECB interview with Wolfgang Feist, and he says it's 4 degrees below room temperature. I stand corrected.

    http://www.aecb.net/feist_videos.php

    Enjoy, Dave

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